xref: /titanic_41/usr/src/lib/libbc/libc/net/bindresvport.c (revision fcf3ce441efd61da9bb2884968af01cb7c1452cc)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 1987 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <sys/types.h>
30 #include <errno.h>
31 #include <sys/socket.h>
32 #include <netinet/in.h>
33 
34 /*
35  * Bind a socket to a privileged IP port
36  */
37 int
38 bindresvport(int sd, struct sockaddr_in *sin)
39 {
40 	int res;
41 	static short port;
42 	struct sockaddr_in myaddr;
43 	int i;
44 
45 #define STARTPORT 600
46 #define ENDPORT (IPPORT_RESERVED - 1)
47 #define NPORTS	(ENDPORT - STARTPORT + 1)
48 
49 	if (sin == (struct sockaddr_in *)0) {
50 		sin = &myaddr;
51 		bzero(sin, sizeof (*sin));
52 		sin->sin_family = AF_INET;
53 	} else if (sin->sin_family != AF_INET) {
54 		errno = EPFNOSUPPORT;
55 		return (-1);
56 	}
57 	if (port == 0) {
58 		port = (getpid() % NPORTS) + STARTPORT;
59 	}
60 	res = -1;
61 	errno = EADDRINUSE;
62 	for (i = 0; i < NPORTS && res < 0 && errno == EADDRINUSE; i++) {
63 		sin->sin_port = htons(port++);
64 		if (port > ENDPORT) {
65 			port = STARTPORT;
66 		}
67 		res = bind(sd, sin, sizeof(struct sockaddr_in));
68 	}
69 	return (res);
70 }
71